1. Technical Field
This invention relates to a multifunction networkable control plug commonly used in hydraulic or pneumatic operated system with one or more valves. More specifically, it relates to a plug with a self-contained electronic programmable controller and visual indicators. The present invention substantially improves the ability to modularize and diagnose a hydraulic or pneumatic control system.
2. Background
Electronic controllers for valves are known.
Sturman et al U.S. Pat. No. 6,257,264 is a programmable electronic valve controller that uses solar power to operate the logic and valve switching mechanics. Though Sturman's invention is programmable, it is not networkable.
Buma et al U.S. Pat. No. 4,826,141 is an electronic controlled air suspension system that uses a series of valves to control a vehicles ride height and level. Buma invention is for a fixed application and is not adaptable to alternate valve types.
Bronacorsi et al U.S. Pat. No. 5,522,431 is a solenoid valve control system that incorporates individual controllers inside one manifold that can be expanded. Though Bronacorsi's invention is modular, it does not provide visual feedback on each individual valve.
The aforementioned prior art of electronic valve controllers do not incorporate a networkable plug with self-contained electronic programmable controller and visual indications of operating status and error states.
The conventional way of electronically controlling one or more mechanical valves is achieved by using a programmable logic controller or a logic controller variant. The logic controller provides electrical current to energize a coil that is built into or attached to the valve.
The energized coil will alter the valve state to allow fluid or gases to pass. Typically one logic controller would control multiple valves and is located at a remote location away from the valves in an environmentally safe compartment. The logic controller would have a separate set of electrical wires branched out to each valve.
Logic controllers are specifically programmed for a particular valve and operation. Typically, the control system for industrial machinery is a closed loop design. A close loop control system is a control system with an active feedback loop. The logic controllers will take analog input data from an electromechanical transducer (i.e. fluid level, position sensor, etc.) and make a logical decision on how to manipulate an output. There are different valves commonly used in industrial machinery. The two most widely used are hydraulic and pneumatic valves. These valves regulate the amount of fluid or gas that is allowed to pass through the system. The fluid or gas that passes through the valves physically moves a mechanical device such as a piston or bladder. This movement translates into mechanical work.
Hydraulic valves operate at a variety of different frequencies and duty cycles. The amount of fluid that is allowed to pass can be incrementally increased from 0 to 100 percent depending on the duty cycle or current supplied. Pneumatic valves typically are either fully opened or fully closed. These valves operate at a variety of voltages. Precise control of the valves is needed to accurately manipulate machinery. Therefore, it is important that the controller have constant, accurate feedback and execute logic commands near real time.
As more systems and machinery are automated, it is required that logic controllers be networked together. Typically this is accomplished by using Ethernet, serial RS232/RS422, Controller Area Network bus or fiber optics communications. The ability to network controllers together provides near real-time data to be transferred to other remote logic controllers. The networked data can be processed by a neighboring controller(s) or monitored remotely by a machine operator. Networking allows system expansion and the ability for the system to provide feedback.
Diagnosing a system that is malfunctioning can be challenging. The time to find and diagnose an issue can be compounded by the complexity of the system. Typically, if there was a problem with a complex system, a subject matter expert of that particular control system would be consulted to diagnose the problem. In other cases, the cause to a malfunctioning system can be very simple. The valves may malfunction when they are overheating or frozen. The connections to the valve from the controller can disconnect causing a system malfunction. In some cases a disconnected valve could cause catastrophic failure or even seriously injury to personnel. The analog input to the controller could also become disconnected and cause invalid logic decisions creating the same malfunction symptoms as a disconnected or stuck valve. Finally, the network or controller could be damaged and prevent the entire system or machinery from operating. A good control system has safety measures in place to perform self-diagnostics and communicate when a malfunction has occurred. These self-diagnostics and safety measures are not typically built into logic controllers and require additional configuration considerations.
In the disclosure that follows, a new design for an electronic valve controller is introduced that provides modularity, automated safety, and visual feedback in a small, lightweight, low cost plug.